Pathogenicity of potato sclerotial isolates of Rhizoctonia solani to potato shoots

Abstract

A rapid method for testing the pathogenicity of Rhizoctonia solani Kühn [= Thanat-ephorus clicumeris (Frank) Donk] to potatoes is described. Using this method, isolates established from sclerotia on seed potatoes were tested for pathogenicity to the variety ‘IIam Hardy’. Of the 294 isolates studied, more than 50% were either moderately or strongly pathogenic, approximately 8% weakly pathogenic, and less than 42% non-pathogenic. The significance of these findings is discussed.